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Our Verdict (Best for)
The GE GXRQ18NBN under sink RO offers good day-to-day usability, producing plenty of filtered water that also tastes and smells great. But the system is extremely slow to prime, and has no shut-off valve on the feed water inlet or tank connector. On the plus side, it delivered excellent results in our lab testing, removing most contaminants to below detection levels. The GE also holds 97 NSF certifications for contaminant reduction. Still, more cons include missing items (Teflon tape and bleach), very costly maintenance, and a high number of customer complaints. Wastewater is also a serious issue – while we measured a pure-to-waste ratio of 1:2:25 without the tank, with tank, the spec sheet lists a highly wasteful ratio of 1:10.19. Bottom line: Not bad but there are better ROs out there.
The GE GXRQ18NBN is a tank-based under sink reverse osmosis system that requires a plumbing connection. It’s designed for use as a drinking water filter and can purify both tap water and properly disinfected well water.
As usual, we’ve tested the system with our own hands:
- Hands-on experience: We installed/assembled, used, and maintained it.
- Filtration effectiveness: We sent an unfiltered and a filtered tap water sample to a professional lab for analysis in order to determine real-life contaminant reduction capabilities. Plus, we checked for NSF certifications and other test data.
- More testing: We performed a taste & odor test, a filtration speed test, a tank-filling speed test, a usable water test, and a wastewater test.
- All other product aspects: We considered initial + long-term cost, product warranties, additional features, frequent customer complaints, etc.
Contents
Overall Rating: /5.00
Filtration: /5.00
Usability: /5.00
Costs: /5.00
| Type: | Under Sink Reverse Osmosis System |
| Price (May 5, 2025, w/o Short-Term Sales): | $229.99 |
| Estimated Yearly Cost (May 5, 2025): | ~$320 |
Overall Rating: /5.00
What We Like Most
- Achieved excellent results in our lab testing for contaminant reduction.
- Filtered water tasted clean and had no smell.
- Holds NSF certifications for 97 contaminants against NSF standards 42, 53, 58, 401, and P473.
- Easy to set up, prime (extremely slow), use, and maintain.
- Looks and feels well-made, simple yet solid faucet.
- Tank fills relatively fast and is large enough for day-to-day.
- Filter change indicator (on faucet).
What We Don’t Like
- Very high water waste (1:2.25 pure:waste ratio without tank; spec sheet says 1:10.19 with tank).
- Instructions had items not included with the kit (Teflon tape and bleach).
- No shut-off valve on feed water inlet or tank connector.
- Very expensive annual maintenance costs due to shorter filter life (below average purchase cost).
- Notable 3rd-party customer complaints on amazon.com, homedepot.com, and geappliances.com (mostly about leaking and slow flow).
How the GE GXRQ18NBN Compares to…
10 Other Under Sink Reverse Osmosis Systems
In this video, Sara highlights our under sink RO top picks. The GE GXRQ18NBN was included in our testing, but didn’t make the cut.
Please note: Our full guide on the best under sink reverse osmosis systems is available here.
Video Chapters + Comparison Sheet
- Link to Comparison Sheet
- 00:00 – Intro
- 00:22 – What’s New?
- 01:11 – Our 11 Under Sink ROs
- 01:54 – How We Tested & Rated
- 05:08 – Our Recommendations
- 06:11 – Best Overall (Cloud RO)
- 20:57 – 2 Best Tankless Units (Waterdrop G3P600 & X12)
- 35:38 – Highest Filtration Score (Aquasana SmartFlow)
- 37:22 – Made in USA (USWS All American & Home Master TMHP-L)
- 41:28 – Budget Pick (APEC ROES-50 Essence)
- 42:50 – Summary
18 Other Under Sink Water Filters
In this video, Sara highlights our under sink water filter top picks. The GE GXRQ18NBN was included in our testing, but didn’t make the cut.
Please note: Our full guide on the best under sink water filters is available here.
Video Chapters + Comparison Sheet
- Link to Comparison Sheet
- 00:00 – Intro
- 00:34 – How We Tested & Rated
- 01:53 – Our Recommendations
- 03:01 – Best Overall (Cloud RO)
- 15:11 – 2 Best Tankless ROs (Waterdrop G3P600 & X12)
- 27:26 – Best Non-RO Filter (Epic Smart Shield)
- 31:22 – Highest Filtration Score (Aquasana SmartFlow)
- 32:02 – Made in USA (USWS All American & Home Master TMHP-L)
- 32:34 – Budget RO Pick (APEC ROES-50 Essence)
- 32:51 – AO Smith AO-US-200 & Culligan US-EZ-4
- 33:34 – Summary
Full Analysis of the GE GXRQ18NBN
Filtration: /5.00
1. Lab Results: /5.00
Remember that our before vs after lab comparison is not an exact science. It’s informational and subject to variability, inaccuracies, and interferences caused by natural fluctuations in water quality, accidental contamination, human error, instrumentation issues, and more. Furthermore, our lab-testing is limited to those contaminants present in our water supplies and at their respective concentrations. As such, it can only give us a general idea for how effective a certain water treatment product might be.
Lab Results Chart
| Potentially Harmful | Aesthetic Issues | Feed Water Level | Filtered Water Level | Reduction Rate | |
| Water Disinfectants | |||||
| Chlorine (mg/L) | ✖ | ✖ | 1.7 | 0 | 100% |
| Disinfection Byproducts | |||||
| Bromodichloromethane (µg/l) | ✖ | 2.71 | 0 | 100% | |
| Bromoform (µg/l) | ✖ | 3.31 | 0 | 100% | |
| Dibromochloromethane (µg/l) | ✖ | 5.15 | 0 | 100% | |
| Chloroform (µg/l) | ✖ | 1.14 | 0 | 100% | |
| Metals | |||||
| Copper (mg/L) | ✖ | ✖ | 0.07 | 0 | 100% |
| Barium (mg/L) | ✖ | 0.04 | 0 | 100% | |
| Boron (mg/L) | ✖ | 0.06 | 0.06 | 0% | |
| Lithium (mg/L) | ✖ | 0.01 | 0 | 100% | |
| Strontium (mg/L) | ✖ | 0.46 | 0.01 | 98% | |
| Salts | |||||
| Nitrate (N) (mg/L) | ✖ | 1.26 | 0 | 100% | |
| Fluoride (mg/L) | ✖ | 0.38 | 0.19 | 50% | |
| Other | |||||
| Uranium (µg/L) | ✖ | 1 | 0 | 100% | |
| RO Salt Rejection | |||||
| TDS (mg/L) | ✖ | 294.6 | 10.8 | 96% | |
| Impurities NOT Detected in Unfiltered Tap Water Sample | |||||
| Explanation: | |||||
| Full Removal | |||||
| Considerable Reduction | |||||
| Concentration More Than Double of Unfiltered Water Sample | |||||
| Potential Leaching Reached or Exceeded the Strictest Public Health Guideline We Could Find | |||||
*100% means reduction to below the minimum detection level. To learn more about our testing procedures check our editorial guidelines.
Link to Filtered Water Report
Link to Unfiltered Water Report
Usability: /5.00
Costs: /5.00
Please note: This page is still a work in progress. Additional content and details will be added shortly – stay tuned!
About the Author(s)
Sara has been a lifelong home-improvement fan (she’s been hooked on This Old House since she was five) and taught herself any project she didn’t already know by watching YouTube tutorials. She is also an award-winning filmmaker. Armed with this skillset, Sara installs, primes, samples, uses, and maintains nearly every point-of-use water treatment systems we test – then brings her results to life on camera for our YouTube channel.
Raoul has a background in mechanical engineering and has been writing about home water treatment since 2015. He designs our product review processes, analyzes the results, and ties everything together. As editor-in-chief, he tries hard to keep the whole operation running smoothly behind the scenes.